Caller identification (caller ID) is typically supported at customer premise equipment (CPE) as a feature offered by a service provider. Additionally, most CPE's (like answering machines) permit the retrieval of information using a call-in procedure typically with a built in security mechanism. Such security systems may include a password access security system. Caller ID permits the CPE to detect and display information about an incoming call. There are existing standards that permit this information to be exchanged between a central office (CO) or a Stored-Program Control Switching System (SCPS) and the CPE. Two common information exchange types that have been standardized include:
1) Type I: In this mode of operation, the phone at the CPE is on-hook. The caller ID information is sent to the CPE by the SCPS as frequency shift key (FSK) information when power ringing is applied. This mode does not directly support the concept of an off-hook signaling protocol.
2) Type II: This mode is a superset of the Type I mode of operation. In addition to supporting Type I signaling, this mode of operation supports an off-hook caller ID feature in conjunction with call waiting. The CO sends a CPE Alerting Signal (CAS), which is to be acknowledged by the CPE. This is followed by a Frequency Shift Key (FSK) data burst that embeds a single message or multiple messages according to some specified format.
A typical system, which supports caller ID (Type I and Type II) functionality, is shown in FIG. 1. A plain old telephone system (POTS) line 10 connected to a network 8 is terminated into a caller ID module 12 which is then connected to a telephone handset 14. Caller ID module 12 displays telephone numbers of remote handsets 15 when they call telephone 14. For supporting a Type I Caller ID function, there is no information exchanged between the handset 14 and the caller ID module 12. In this case, when the handset 14 is on-hook, incoming caller ID information gets automatically recorded and can be displayed on a display on the handset 12. Playback of this information can be accomplished either at a CPE 16 or remotely using a call-in procedure with some built-in security (such as a password).
It would be advantageous to provide a method and system, which provides a remotely initiated three-way calling feature, which employs numbers stored in a CPE. It would also be advantageous to provide a system and method which implements a callback mechanism implemented based on stored numbers in the CPE.